Control for subvacuous condition of periodically-fired boilers



March 8 1927. v. T. BRIGHAM CONTROL FOR SUBVACUOUS CONDITION OF PERIODICALLY FIRED BOILERS Filed Aug. 9, 1926 2 Sheets-Sheet 1 Jmw INVE{V TOR.

/ ATTORNEYS.

1,620,005 March 1927' v. T. BRIGHAM CONTROL FOR SUBVACUOUS CONDITION OF PERIODICALLY FIRED BOILERS Filed Aug. 9, 1926 2 Sheets-Sheet 2 A TTORNEYS is stopped and the unreplenished eva ora-.

Patented Mar. 8, 1927;

UNlTED STATES PATENT OFFICE.

VERNON T. BRIGHAM, 0F DES MOINES, IOWA.

common FDR snnvacnons connrrron or ,rnaronreannr-rrnnn BOILERS.

Application filed August 8, 1928. Serial No. 128,283.

ently due to the fact that soon after thefire has passed its hottest point the condensation taking place in the legs of the radiators becomes increasingly more rapid than the evaporation taking place in the boiler under which condition the vacuum in the boiler, steam line, and radiators begins to steadily increase until the pressure in the boiler is lowered below that of the receiving tank. The differential between the two parts of the system resists and overcomes the forces which normally operate to return the water to the receiving tank. When such a condition arises the flow to the return tion taking place inthe boiler may ower the water level of the boiler, particularly of the sectional cast iron boiler, to a point endangering the crown sheet.

Many suggestions were made as to the causes underlying the lowering of the water line in the boiler, it being suggested that there was a stoppage inthe return line flow, or that the boiler was dirty, and so forth, but aftergreat care had been taken to remedy any difficulties of the character outlined there was still a periodic recrudescence of the trouble and it is believed that the explanation offered above is a true explanation of the difficulty.

In order to remedy the condition above set out, I have produced ap aratus which is set into operation by a ro in boiler pressure to a point lower than t e pressure in the receiving tank, said apparatus immediately starting the vacuum pump to lower the pressure in the receivingtank sufliciently to start the flow of all water which may be locked in the distributing system.

With the general objects named in View, the invention consists in certainnovel and useful features of construction and organization of parts as hereinafter described and claimed; and in order that it may be fully understood, reference is to be had to the accompanying drawing, in which L- Figure 1 is a general view of what is known as the Thompson vacuum heating system together with the ap aratus of the invention, it being understoo however that the device of the invention is not restricted to use with such system.

Fi ure 2 is a section through the pressure regu ator for control of the vacuum pump.

Figure 3 is a section through a boiler-actuated pressure device forming a part of the invention.

Figure 4 is a section through a float valve control. I

Figure 5 is an enlarged section to illustrate the operating valves of the Thompson system.

Figure 6 is a central vertical section through a modified T-coupling forming a part of the invention."

In the said drawings where like reference characters identify corresponding parts in all of the fi res 1 is a vacuum heating boiler equippe with a distribution line 2, a gage line 3,, and a return line 4. The return line 4 leads to a receiving tank 5 and is controlled by a check valve 6 to prevent pressure in the boiler forcing the flow of water in the reverse direction throu h the system. A. return line 7 leads to t e tank 5 at its opposite side and in said return line is a suitable strainer 8 and a check valve 9 to prevent pressure ,in the tank from forcing the water in the reverse direction through the system, as will be readily understood. Mounted on top of the tank 5 is an electric motor #10 connected to drive an air pump 11. Secured also to the tank is a valve box 12 which, adjacent one of its ends, contains a double acting valve 13 alternately closing and opening a pair of ports 14 and 15, the port 14 leading to the atmosphere and the ort 15 into the receiving tank 5. At t e other end of the valve box are a pair of valves 16 and 17 mounted on the samev stem and respectively controllin the receiving tank an a port leading to the atmosphere as clearl disclosed in the drawing, Figure 1. Leading from the valve a port leading tobox between the ports controlled by valves 16 and 17, is an air entry line 18 controlled by a check valve 19 and leading to the air pump 11. The air pump sucks in air from the tank or from the atmosphere according to the positions of valves 16 and 17 through pipe 18 and forces it out through pipe 20 to trap 21 to collect oil and greases which may escape from the pump, and from said trap a line 22 leads to the valve box 12 at a point between ports 14 and 15, so that air forced through pipe 22 may escape into the tank or to the atmosphere.

The stems 23 and 24 of valves 13, 16 and 17 are pivotally connected to opposite ends ofa T-shaped rocker arm 25 within the tank, said rocker arm being pivotally fastened at 1ts lower end to a crank arm 26 which is rigidly secured in any suitable manner to the stem 27 of a float- 28 within the tank. All of said parts being pivoted to a bracket 29 extending downwardly in the tank. In order to secure positive opening and closing of the valves, a spring trip mechanism 30 is mounted for quickly opening and closing said valves after the float'has moved the mechanism to a predetermined point. As none of this mechanism forms a part of the invention, it is not particularly described in detail other than to show the general mode of operation to disclose properly the functions of the vacuum system as regards the novel parts of the invention.

Tapped into the receiving tank-5 at a suitable point is an air line 31 leading to a pres-- sure actuated regulator 32 mounted within a box 33, said box being open to the atmosphere as at 34. Extending through the opening 34 is the actuating stem 35 of the pressure regulator, said stem 35 being pivotedintermediate the ends of a pivoted lever 36 to the free end of which is secured a retractile spring 37. Carried by the lever 36 at an intermediate point is a stud 36 which is adapted at times to interlock with the notch 38 in a downwardly extending lever 39, said lever 39 being under tension of the spring 40. The lever 39 is secured to the end of an'oscillating arm 41 which at its opposite end carries any suitable switch mechanism 42. This mechanism also is not described in detail as it forms no part of the invention. I

The valve stem 24 of valves 16 and 17 extends upwardly and at its upper end carries any suitable switch mechanism 43. The switches 42 and 43 are operative to set the electric motor 10 in operation by effecting operation through the starting box 44.

All of the mechanism heretofore described is common and well known in the art, but in order that a full understanding of my invention may be had, I will now proceed to give a short rsum of the normal operation of the vacuum heating system employing the Thompson mechanism herein illustrated. Referring to the position of the parts shown in Figure 5, the receiving tank 5 having been emptied by the forcing of the water into the boiler, the condensation switch 43 is open and the pump 11 is in operation by the closing of the pressure regulator switch 42 to suck air from the receiv ing tank 5 through the port controlled by the valve 16, through pipe 18, the line 20, the oil and grease trap 21, line 22 an". finally exhausting said air through the port 14. The pump continues to draw air from the receiving tank 5 until the suction from the tank 5 operates through the line 31 on the pressure regulator 32. The stem 35 of the regulator is drawn downward and effects operation of the lever 36. At a predetermined point the end of the lever 39 rides quickly under the impetus of the spring 40 upon a roller on the stud 36 and effects opening of the circuit through the switch 42 and consequently eflects the stopping of the pump. The vacuum in the return line and tank is left under positive control of the vacuum regulator and can be altered only by a readjustment of the vacuum adjusting screw 37*. Thus the tank 5 and system are sealed against the atmosphere by the closing of the check valve 19, both switches 42 and 43 are opened stopping oporation-of the pump and condensation from the return line and radiators, unless prevented by a stoppage in the pipes or by a sub-vacuous condition in the radiators and boiler, commences to flow into the receiving tank 5 under gravity through the return line 7 and such flow of condensation is also assisted by the vacuum in the receiving tank. As the liquid level in the tank rises, the float 28 is elevated and at a. predetermined point the trip mechanism 30 throws the valves 13, 16 and 17 to their reversed positions shown in Figure 1, thus closing the circuit through the condensation switch 43 and starting the operation of the motor, the tank at this time standing full of water to a predetermined point. As the valves 15, 16 and 17 stand in the positions shown in Figure 1, the operation of the motor through the switch 43 effects operation of the pump to compress the air in the tank by drawing it from the atmosphere through theopen box 18*, port 19, valve 17, the line 18, line 20, the trap 21, line 22, valve box 12, and through port 15 into the tank, thus driving the water into the boiler through line 4 past check valve 6 into the boiler.

From the above description, it will be apparent that no mechanism is provided to equalize the pressure in the boiler and receiving tank should .a stoppage in the return line occur, such as a high vacuous condition in the legs of the radiators and steam lines effecting a stopping of the flow through the return line 7 as stated in the openingparagra h of this application.

I shal now proceed to describe the structure of the invention as working in con-- junction with the mechanism hereinabove set out. Tapped in the gage line 3 is a lead line 44 leading to a pressure diaphragm 45 mounted in a box '46 closed to the atmosphere. The stem 47 of the diaphragm extends through a packing gland 48 and is pivotally connected in a slot 49 in a lever 50. The end of the lever 50 is slotted and rounded for slight pivotal action and rests on an adjusting nut 51 threaded on a screw 52 carried by the box 46, said lever being under tension of a spring 53 which may be adjusted by nut 53*. This construction is adopted in order to allow for variation in the normal position of various diaphragms when first set up in the system. The other end of the lever 50 is pivotedvas at 54 to a valve stem55 of an air valve 56 for openin and closing valve seat 57 formed in a va ve casing 58. Connected to the pressure box 46 exterior of the diaphragm 45 is a pressure line 59 leading to an enlarged por-.

tion 60 connected to the float valve chamber 61, the lower end of said chamber 61 being in communication with the return line 7 of the heating system. Mounted in the float chamber 61 is a float 62 controlling a needle valve 63 to admit air at certain times through port 64 and up pipe 65 into the enlarge portion 60, it being apparent that when water stands in the-chamber 61 to a sufficient height, the float 62 is operated to create an air leak through the pipes de scribed, thus permitting atmospheric pressure to drive water out of pressure line 59 into the receiving line 7, a necessary condition to establish a proper balance between line 44 to the boiler and line 59 to the re turn line 7.

The valve 58 controls the admittance of air through a pipe 66 from the atmo phere down through a pipe 67 to a T-coupling 68 mounted in the pressure line 31 leading from the return line tank. Referring to Figure 6, it will be noted that the T has an en arged passage 69 leading to the vacuum regulator and 'a small to the return line tank.

Having thus described the new mechanism of the invention, shall now proceed to describe in detail its mode of operation in conjunction with the standard equipment of a vacuum heating system. Referring to Figure 3, it'will be readily apparent that the diaphragm 45 is internally subjected to the pressure of the boiler and externally subjected .to the pressure in the return line. As we are dealing with a vacuum system, that is with a system handling pressures lower thanthat of the atmosphere, it will be evident if return water ever stands passage 70 leadingin the return line will contract the diaphragm 45 and effect the opening of the valve 58. Air under atmospheric pressure immediately rushes through the leads 67 and through the T-coupling 68 and thus effects expansion of the diaphragm 32 to close the switch 42 to set the motor into operation in order to effect an exhausting of the pressure within the receiving tank to a level lower than normally maintained by the pressure-regulator. The motor will continue in operation-as long as the pressure in the tank is higher than the pressure in the boiler, thus a vacuum is produced in the receiving tank which efi'ectively balances the vacuum in the boiler and again starts the flow of water from above the trap through the return line 7 to the tank 5. The water in said tank eventually reaches such a height as to trip the valves and start the production of a pressure in the tank to force the water to the boiler. In this connection, it will be apparent that there will be a leakage of air through the small port 70 in the T-coupling 68, but such leakage is of short duration and in insufficient amount to appreciably affect the pressure in the tank or in the return line. Free circulation throughout the entire system is thus quickly established,

and through the actuation of the diaphragm 45, the pressure in the return line is maintained at a lower level than the pressure in the boiler and the boiler is thus protected until the next firing period. It is desirable to point out that an additionaladvantage is obtained by the increased heating or steaming range of the boiler through the added increase of the vacuum impressed at this period upon the receiving'tank. With the mechanism of the invention, it will be evident that heating systems set to operate under very low vacuum will be automatically controlled to operate at a higher vacuum whenever the aforesaid sub-vacuous condition arises and that such a system will have the additional advantage of the increased steaming range due to' such increase in vacuous conditions.

From the above description, it will be apparent that have produced mechanism which carries out the objects of the invention, and while I have described and claimed the preferred forms thereof, it is to be Gal understood that I reserve the right to make all changes properly falling within the spirit and scope of the appended claims.

I claim:

1. In a vacuum heating system, the combination with a boiler, return line, and a pump, of a connection between said boiler and return line, and pressure actuated means in said connection for efl'ecting operation of said pump.

2. In a vacuum heating system, the combination with a boiler, return line, and pump, of a connection between said boiler and return line, an air inlet valve, an electric switch, and pressure actuated means to open said valve to permit the entry of air to close said switch for the operation of the pump.

3. In a vacuum heating system, the combination with a boiler, return line, receiving tank, vacuum pump, and a pressure regulator aflt'ected by the pressure in said receiving tank to start operation of said pump, of a connection between said boiler and return line, a diaphragm in said connection having its opposite sides exposed to the pressure in the boiler and return line respectively, a valve controlled air inlet to said pressure regulator, and a connection from said diaphragm for controlling said valve controlled air inlet.

4. In a vacuum heating system, the combination with a boiler and return line, of a pump for forcing fluid from said return line into the boiler, and a connection for alfecting operation of the pump when pressure in said boiler drops below the pressure in the return line.

5. In a vacuum heating system, the combination with a boiler and return line, of a pump for forcing fluid from said return line into the boiler, and a connection from said boiler to the return line comprising a, diaphragm affected jointly by the boiler and return line pressures for starting the operation of the pump when the return line pressure exceeds the boiler pressure.

6. In a vacuum heating system, the combination with a boiler and return line, of a pump for forcing fluid from said return line into the boiler, a pressure-actuating switch for effecting operation of said pump, a pressure-operated diaphragm exposed at its opposite sides to the pressures in the boiler and return line respectively, and an air inlet controlled by said diaphragm and adapted at times to admit air to said pressure-ac- V tuated switch.

the return line equal or lower than the pressure in the boiler.

8. In a vacuum heating system, the combination with a boiler, of a return line, a return line box, and a pump, valved connections to said box and pump whereby the pump may be operated to eflect an increase or decrease in the pressure within said box, a by-pass around said box to the boiler,-a diaphragm closing said by-pass, and means affected by a deflection of said diaphragm due to decrease in the pressure within the boiler to efl'ect operation of the pump to lower the pressure in the return line box.

- 9. In a vacuum heating system, the combination with a boiler, a return line leading to said boiler, an air pump, valved connections in said return line whereby the pump may be operated to effect an increase or decrease in the pressure within said return 1 line, a by-pass around said pump 'to the boiler, a diaphragm closing said by-pass, and means affected by operation of the diaphragm upon decrease in the pressure within the boiler to operate said pump.

10. In a vacuumheating system, the combination with a boiler, return line, receiving tank, vacuum pump, and a pressure regulator affected by the pressure 1n said receiv- .a pressure in the boiler below the pressure in the return line to effect actuation of said pump.

12. In a heating system, a boiler having a distribution line and a return line WhlCh are subjected to a periodic vacuous condition at a point remote from said boiler, a receiving tank connected in said return line, a pump connected to said receiving tank for increasing-or decreasing the pressure in said receiving tank, anda connection between said return line and boiler for actuation of said pump to lower the pressure in the receiving tank when the boiler ressure falls below the return line pressure due to the production of a vacuous condition at the remote point. 1

In witness whereof I hereunto aflix my signature.

' VERNON T. BRIGHAM.

ing tank to start operation of said pump, of

DISOLAIMERs *1,620 ,005. Vem0n T. Brigham, Des Moines,' Iowa. CONTROL FOR SUBVACUOUS Ctnvnr rrous OE'PERIODICALLY-FIRED BOILERS. Patent dated March 8, 1927.

Disclalmer filed March 18, 1929, by the patentee.

Hereby disclaims: A

1. The fpress'ure actuated means recited in the last clause of claim 1, except a pressure actuated means which is operative only. when the pressure in the boiler is.

below the pressure inv the return line.

2. The subject matter of claim 4, except in aconstruction -in which the connection for effecting operation of the pump is operative only when the boiler pressure is below the return line pressure.

3. The subject matter of claim 5, except in a construction in which the connection is operative only upon the production of a pressure in the boiler below the pressure a in the return line.

4. The subject matter of claim 7. p p 5. The means recited in the last clause of claim 11, except-a means whlch 1s actuated only uponthe production of a pressure in the boiler lower than the pressure in the return line. q

[Oflieial Gazette April 9, 1929.] 

